Recording rain gauge



Feb 24, 1953 s. E. NOTHMANN Erm. 2,629,258

l RECORDING RAIN AUGE Filed March 1, 1951 5 Sheets-Sheet l Feb. 24, 1953 s. E. NOTHMAN l-:TAL 2,629,258

l RECORDING RAINV GAUGE Filed arch 1, 1951. 3 Sheets-Sheet 2 Varg1-.2.

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Feb. 24, 1953 Filed March l, 1951 S. E. NOTHMANN ETAL RECORDING RAIN GAUGE sin `Jill 3 Sheets-Sheet 3 @fly/Vp fie/Eb MANY/ Patented Feb. 24, 1953 OFFICE RECORDING RAIN `GAUGE Shimshon Ernst Nothmann and Benno Friedmann, Tel-Aviv, Israel Application March 1, 1951, serial Nolzlsos In Israel March 8, 1950 f 2 Claims. j `1 Thisinvention relates to recording rain gauges of the weighing or balance type wherein a balance beam carries at one end a counterpoised'rain collector vessel and merges at the other end with an arm provided with a writing implement for recording on a chart the increase of weight of the collector due to the collecting rain water. When the collector has taken in so much water that the writing implement reaches the end of its recording range at the upper edge of the chart, the collector is emptied.l

In some known rain gauges of this kind the collector is emptied automatically in that -the balance beam is made, in a certain position, to strike a control member which is thereby made to open an outlet in the lowerv part of the collector. This arrangement has the drawback that the actuation of the control member by the balance beam brakes the latter whereby the rain record is falsified. The present invention has the object to overcome this drawback.

The invention consists in a rain gauge of the kind referred to, wherein the collector encloses a float arranged to operate an outflow control member so as to allow the outflow of water from the collector when the oat reaches a pre-determined high level.

It is preferred to make the outlet in the form of an overow Siphon cooperating with a bell arranged to be lifted by the float and to be dropped when the latter has reached a predetermined level, and thereby to start the emp tying of the collector by siphon action.

An embodiment of the invention is illustrated, by way of example only, in the accompanying drawings in which:

Fig. l is a side elevation of a rain gauge of the kind to which the invention refers, part of the casing being broken away; Y

Fig. 2 is a cross section on line II--Il of Fig. l;

Fig. 3 is a vertical axial section, drawn to a larger scale, of the collector which is constructed in accordance with the invention.

The arrangement of the rain gauge as shown in Figs. 1 and 2 is known in principle. The instrument is enclosed in a casing l closed at its top by a lid 2 including a collecting surface 3 of standardized area. This surface is drained by a conduit 4 which opens into a funnel (not shown) leading into the bottom part of the upright-cylindrical collector G. The collector has a hood 5. Its bottom is centrally depressed and forms a pit l from which an outflow tube B opens freely into the bottom part of the casing. By means of laterally extending inverted bearings `balance the collector.

9 the collector rests-on knives l0 provided at one end of each longitudinal vmember Il, Il of a.

forked balance beam 'whose transverse member l2 rests on knives I3 supportedl on bearings I4. The latter are supported by short columns l5 mounted on rails Iliwithin the casing. A balance weight i1 is mounted on an arm I 8 secured to the member i2 of the beam in order to counter- `A further weight I9 is slidably arranged on an extension I l of the beam member Il and serves for the ne adjustment of the beam. In continuation of the beam member Il a writing implement 2n extends to the chart drum 2l. lA window 22 is provided in the casing in order to allow observation of the chart. The collector is so poised by the two weightsthat when it is empty. the writing implement occupies zero position at or near the lower edge of the recording chart. The capacity of the collector is so calculated that emptying' thereof (see below) takes place when the writing implement has nearly reached `the upper edge of the chart.

Fig. 3 shows the arrangement of the collector in accordance with this invention. In the pit 1 of the collector bottom small supporting blocks or projections 23 for the siphon bell 24 are provided. The vertical outlet tube 8 projects through the pit bottom up into the collector to about half the height of the latter, and the bell is so high that when it rests on the supports 23 its top is slightly above the upper end of the tube 8. The collector houses a float 25, e. g. a hollow sheet metal ring, which may be guided by suitable guide means (not illustrated) so as to be able to move vertically but not to displace itself laterally or angularly. The float carries a yoke 26 whose transverse member has an aperture 2l.

` In lugs 28 provided in central position of the transverse yoke member., a hook 29 is pivoted. It serves for interengagement with a hook Si) fixed to the top of bell 24, and is urged into engaging position by a weight 3l. In this position, the tail 29' of hook 29 lies beneath the aperture 2l. Above the latter a pin 32 projects downwards from the top part of the collector.

As rain water rises in the collector to Ia level above the pit l, the oat 25 begins to rise and takes the bell 24 with it until the pin 32,` penetrating through the aperture 21, strikes the tail 29 of the hook 29 which thereby swung round its pivot anticlockwise and'releases the bell. The latter drops and, in the `known way of overflow siphons, pushes into the v' tube 8 a quantity of Water suicient to start uninterrupted outflow from the collector until the latter is nearly empty. The float sinks back onto the collector bottom, the hook 29 strikes hook 30 on its chamfered edge, is thereby pushed back and, after passing the hook 30, urged back into interengagement therewith by the weight 3|, and thus the operation of the gauge can continue. The sudden lessening of the weight of the collector makes the latter rise and thereby lowers the writing implement back into zero position.

It has been ascertained that with a rain gauge of conventional size, the emptying operation can be completed in a few seconds so that there isv virtually no interruption of the recording operation.

Obviously the rise of the iloat within the collector is an internal matter and does not affect the intended normal operation of the balance which is subject to no other influence than the increase of weight of the collector by the rain water and the drop of weight owing to the outow of Water `from the collector So that the record. truly reflects the processes which it is intended @Q SHOW# W@ @Mimi l.. A recording rolo galileo Comprising lo oombination. o two-armed balance, boom, a recording implement at the ond o ooo arm of the balance beam, a rain collector vessel, balanced. on .the other arm of the balance beam, a weight counter.- poising the collector vessel, a vertical outllow tube in the bottom of the collector vessel and extending upwards into the latter, a Siphon bell Within the Collector vessel enclosing Said loner extension ofi the outtlow tubo, ,o lloot in tho co1- lootor vessel. adopted, to .riso 'therein in. rrooor non to the amount ot rain Water oollootille in the vessel, detachable means connecting the` Siphon bell to the float-tor allowing the float as it rises to lift the bell, and means for detaching said connecting means in the pre-determined highflevel position of the float in the collector in response to arrival of the float at said highlevel position, thereby allowing the siphon bell to drop back and thereby to start the evacuation of the rain water from the collector vessel by Siphon action.

2. A recording rain gauge comprising in combination a two-armed balance beam, a recording implement at the end o f one arm of the balance beam, a rain collector vessel balanced` on the other arm of the balance beam, a weight counterpoising the collector vessel, a vertical outflow tube in the bottom of the collector vessel and extending upwards into the latter, a Siphon bell Within the collector vessel enclosing said inner extension of the outow tube, a float in the collector vessel adapted to rise therein in proportion to the amount of rain water collecting in the vessel, a yoke mounted on the iloat and overhanging the Siphon bell, interengaging hooks respectively secured on top of the yoke and pivoto-lll? mounted oo top of the loolly on abutment in. the collector vessel adopted to Strike one of said hooks` the predetermined high-level position of the float in the collector vessel, and thereby to sever the mutual engagement of the hooks.

Sl-IlMSl-IQN ERNST NOTl-IMANN. oENNo REFERENCES CITED Number Name Date 1.752.620 swindln Apr. 1. 1930 2.468.692 Stevens Apr-2.6.1949

o'rHER REFERENCES,

Article entitled A New Recording Raingauge, by A. Hauer in the Journal of Scientific Instruments, vol. 28, #3, March 1951, pages 84-85. 

